Electric Fields and Potential

PIRA Classification 5B

Grayed Demos are either not available or haven't been built yet

Please note that these tables have not yet been edited to match the equipment that is available within the UW-Madison lecture demo lab. There maybe many items listed within these tables that we either "can not do" or have available.

5B10. Electric Fields

PIRA #

Demonstration Name

Abstract

5B10.10

hair on end

While standing on an insulated stool, charge yourself up with a Van de Graaff generator.

5B10.11

hair on end

Charge Van de Graaff generator with a Wig on the dome and without grounding ball.

5B10.13

pithball plate and flying balls

Place a plate with pith ball hanging on strings on an electrostatic generator. Also place a cup filled with styrofoam balls on an electrostatic generator.

5B10.15

Van de Graaff streamers

Attach ribbon streamers to the top of a Van de Graaff generator.

5B10.15

Van de Graaff streamers

A small stand with thin paper strips is placed on an electrostatic generator.

5B10.15

Van de Graaff with streamers

Show Van de Graaff with paper streamers, then hair on end.

5B10.16

recoiling tentacles

Place the electrostatic plume made out of nylon rope near the other terminal of the Wimshurst machine.

5B10.21

electric rosin

Melt rosin in a metal ladle and attach to a static machine. When the machine is cranked and the rosin slowly poured out, jets of rosin follow the electric field.

5B10.22

electrostatic painting

Clip the can to ground and a metal object to be painted to the Van de Graaff generator. Point out that the paint goes around to the back too, and it is thickest on the edges.

5B10.23

MgO smoke

Fill an unevacuated bell jar with MgO smoke and they will form three dimensional chain-like agglomerates between electrodes.

5B10.23

orbiting foil

Throw a triangle of aluminum foil into the field of a Van der Graaff and it comes to equilibrium mid-air. Give it a half-twist, and it will orbit in a horizontal circle below the sphere.

5B10.24

charge motion in an electric field

A charged ball on a dry ice puck is launched toward a Van de Graaff generator. The motion is recorded with strobe photography.

5B10.25

confetti (puffed wheat)

Confetti (puffed wheat, styrofoam peanuts) flies off the ball of an electrostatic generator.

5B10.25

confetti on electrostatic generator

Confetti flies off the ball of an electrostatic generator.

5B10.25

streamers

Fray the end of a nylon clothesline and charge with an electrostatic machine to show repulsion.

5B10.26

eletrified strings

A bunch of hanging nylon strings are charged by stroking with cellophane causing repulsion.

Aluminum powder bounces between two horizontal plates 1 cm apart attached to a static machine. Metalized pith balls bounce between an electrode at the top of a bell jar and the plate.

5B10.32

Van de Graaff chime

Toss a small foil near the charged sphere (see AJP 32(1),xiv - 5B10.33) and then bring a grounded ball close to show the chime effect.

5B10.33

electrostatic ping-pong

A fluffy cotton ball travels back and forth between an electrostatic generator and a lighted cigar.

5B10.35

electrostatic ping pong

Bounce a conducting ball hanging between two plates charged with a Wimshurst.

5B10.40

fuzzy fur field tank

"Fur" in mineral oil aligns along field lines from charged electrodes.

5B10.40

"velveteens"

Fine black fiber clippings in castor oil are used to show electric field between electrodes.

5B10.40

electric fields between electrodes

Charged electrodes are placed in a tank of mineral oil containing velveteen and the pattern is projected on the overhead.

5B10.40

fuzzy fur field tank

Bits of material suspended in oil align with an applied electric field. Several pole arrangements are shown.

5B10.40

electric field

A pan on the overhead projector contains particles in a liquid that align with the electric field.

5B10.41

repelled air bubbles

A stream of air bubbles in an oil bath are repelled in the region of an inhomogeneous field.

5B10.42

epsom salt on plate

Sprinkle Epson salt on a glass plate with two aluminum electrodes. Tap to align the crystals.

5B10.43

ice filament growth

An ice filament pattern shows the electrical field configuration. Place a PZT transducer on a block of dry ice.

5B10.50

mapping force with "electric doublet

Two pith balls charged oppositely and hanging from a rod are used to map out the field in the region of charged conductors.

5B10.51

plotting equipotential lines

A method for plotting equipotential lines from electrodes in a pan on water.

5B10.52

finger on the electrophorus

Charge and electrophorus., then trace a circle on it with your finger and probe the resulting field with a pith ball on a long thread.

5B10.53

extent of electric field

Hold an electroscope several feet away from a static machine and observe the electroscope leaves rise and fall as sparking occurs.

5B10.54

mapping field potential, voltage

A wire held in the flame of a candle and attached to a grounded electroscope is held near a Van de Graaff generator. Mount two candles on a insulator and attach the second to the case of the electroscope to measure voltage.

5B10.54

mapping potential field

A small alcohol lamp attached to an electrostatic voltmeter can be used to map potential fields.